igraph Reference Manual

For using the igraph C library

Chapter 6. Memory (de)allocation

1. igraph_malloc — Allocate memory that can be safely deallocated by igraph functions.
2. igraph_calloc — Allocate memory that can be safely deallocated by igraph functions.
3. igraph_realloc — Reallocate memory that can be safely deallocated by igraph functions.
4. igraph_free — Deallocate memory that was allocated by igraph functions.

void *igraph_malloc(size_t size);

This function behaves like malloc(), but it ensures that at least one byte is allocated even when the caller asks for zero bytes.

Arguments:

size:

Number of bytes to be allocated. Zero is treated as one byte.

Returns:

Pointer to the piece of allocated memory; NULL if the allocation failed.

void *igraph_calloc(size_t count, size_t size);

This function behaves like calloc(), but it ensures that at least one byte is allocated even when the caller asks for zero bytes.

Arguments:

`count`:	Number of items to be allocated.
`size`:	Size of a single item to be allocated.

Returns:

Pointer to the piece of allocated memory; NULL if the allocation failed.

void *igraph_realloc(void* ptr, size_t size);

This function behaves like realloc(), but it ensures that at least one byte is allocated even when the caller asks for zero bytes.

Arguments:

`ptr`:	The pointer to reallocate.
`size`:	Number of bytes to be allocated.

Returns:

Pointer to the piece of allocated memory; NULL if the allocation failed.

See also:

igraph_free(), igraph_malloc()

void igraph_free(void *ptr);

This function exposes the free() function used internally by igraph.

Arguments:

ptr:

Pointer to the piece of memory to be deallocated.

Time complexity: platform dependent, ideally it should be O(1).